How Does Plasticizer Work
The plasticizing process of plasticizers in plastics can be regarded as a process in which resins and plasticizer low-molecular compounds dissolve with each other, but plasticizers are different from general solvents. Solvents will evaporate during processing, while plasticizers It is required to stay in the polymer for a long time without chemical reaction with the resin and form a solid with the resin. When plasticizer is added, it can increase the flexibility, flexibility, cold resistance and elongation of plastic. Reducing the plastic's hardness, modulus, glass transition temperature, melting point, softening temperature or flow temperature makes the viscosity of the plastic smaller and the fluidity increases, thereby improving the processing performance.
The plasticizing mechanism of plasticizers is generally considered to have the following two types:
1) When the plasticizer and resin melt together, the small molecules of the plasticizer will be inserted between the polymer molecular chains, weakening the attraction between the polymer molecular chains and increasing the distance between them. Increase the possibility of polymer molecular chain movement, reduce the entanglement between polymer molecular chains, so that the resin can undergo a glass transition at a lower temperature, thereby increasing the plasticity of the plastic. It can be seen that the attraction and entanglement between polymer molecular chains are a major reason for resisting plasticization.
2) The molecular structure of the polymer also affects the gravitational force between the polymer molecular chains, especially the nature of the groups on the polymer molecular chain. The strong interaction between the molecular chains with strong polar groups has a non-polar group The force between the molecular chains is small. In order to make the polymer with strong polar groups easy to form, plasticizers can be added. The polar groups of the plasticizer will interact with the polar groups of the polymer, which weakens The gravitation between the polymers is achieved, and the purpose of plasticization is achieved.
It can be seen from the above that the key to the plasticizing effect of the plasticizer is to weaken the force between the polymers